Combination tractors and semitrailers using a fifth wheel are vulnerable to jackknifing on the highway under certain driving conditions. Also the trailer sometimes separates from the tractor during use. To overcome this problem an auxiliary kingpin has been devised as shown in Canadian Reissue Pat. No. 894,111 issued Feb. 29, 1972 to Auto-Mat Safety Devices assignee of Angelo Interisano entitled Safety Device for Tractor-Trailer Hook-Up Mechanism and U.S. Pat. No. 3,556,559 issued Jan. 19, 1971 to Auto-Mat Safety Devices assignee of Angelo Interisano entitled Tractor and Semitrailer Pivot Coupling with Interchangeable Trailer Plate.
Two problems are associated with the above-mentioned Interisano devices, namely (1) the apparatus, which uses a flexible cable for remote actuation of the auxiliary kingpin, is cumbersome and also subject to malfunction, and (2) the rudimentary bumpers associated with the limits of the arcuate travel of the auxiliary kingpin about the main kingpin are inadequate to absorb the shock of a jackknifing trailer.
It is an object of the present invention to provide an improved auxiliary kingpin actuator apparatus for a tractor and semitrailer combination.
It is another object of the invention to provide an improved bumper device for an auxiliary kingpin in a tractor and semitrailer combination.